JPWO2017154672A1 - Dust cover and sealing structure - Google Patents

Abstract

Provided is a dust cover and a sealing structure that improve sealing performance without increasing the number of parts. The seal portion 120 includes an inner peripheral seal portion having a plurality of annular convex portions slidable with respect to the outer peripheral surface of the shaft portion 310, and a dust seal portion slidable with respect to the end surface of the knuckle 400. The third convex part 121c on the most end side of the annular convex part is one end side by the annular concave part 123 recessed from the end face on one end side to the other end side in the seal part 120 and the inner peripheral surface of the seal part 120. And the inner peripheral surface of the third convex portion 121 c is configured to be slidably in close contact with the outer peripheral surface of the flange portion 311.

Description

  The present invention relates to a dust cover and a sealing structure used for a ball joint provided in various devices such as a vehicle.

  2. Description of the Related Art Conventionally, in ball joints provided in various devices such as vehicles, a dust cover is used to prevent water and dust from entering the joint portion and to prevent grease from flowing out from the joint portion. With reference to FIG. 5, the dust cover used for the ball joint which concerns on a prior art example is demonstrated. FIG. 5 is a schematic cross-sectional view of a conventional ball joint and a dust cover attached to the ball joint.

  The ball joint includes a ball stud 300 having a spherical portion at one end of a shaft portion, a socket 200 that supports the ball stud 300 so as to be rotatable and swingable, and a knuckle 400 coupled to the shaft portion of the ball stud 300. Yes. The dust cover 700 is provided on the deformable film-shaped body portion 710, the one end side of the body portion 710, the fixed portion 730 fixed to the socket 200, and the other end side of the body portion 710. And a seal body made of an elastic body integrally having the seal portion 720. The seal portion 720 includes an inner peripheral seal portion 721 that is slidably provided on the shaft portion of the ball stud 300 and a dust seal portion 722 that is provided slidably with respect to the knuckle 400.

  A reinforcing ring 750 is embedded in the seal portion 720. In this manner, by embedding the reinforcing ring 750 in the seal portion 720, the sealing performance by the inner peripheral seal portion 721 and the dust seal portion 722 can be improved.

  Here, for example, as shown in FIG. 5, when the ball stud 300 is tilted to the left in the figure, the left part of the body part 710 is compressed and the right part in the figure is extended. Become. Thereby, in the right part in the figure, the inner peripheral seal portion 721 acts away from the shaft portion of the ball stud 300, and the dust seal portion 722 acts away from the knuckle 400. . As described above, when the reinforcing ring 750 is embedded in the seal portion 720, the inner peripheral seal portion 721 is prevented from being separated from the shaft portion, and the dust seal portion 722 is prevented from being separated from the knuckle 400. Is done.

  However, under the low temperature environment, the rubber inner peripheral seal portion 721 and the dust seal portion 722 are remarkably lost in elasticity. Further, permanent deformation due to compressive deformation at low temperatures may cause gaps between the inner peripheral seal portion 721 and the shaft portion of the ball stud 300 and between the dust seal portion 722 and the knuckle 400. Thereby, there exists a possibility that a sealing function may fall.

  As a countermeasure, a technique for supporting a dust cover by attaching a retainer to a shaft portion of a ball stud is also known (see Patent Documents 1 and 2). However, in this case, since a retainer is required, the number of parts increases and the cost also increases. Moreover, there is also a concern that by supporting the dust cover with the retainer, the seal portion in the dust cover is pressurized more than necessary, and the slidability is deteriorated. If the slidability is lowered, the film-like body portion of the dust cover is twisted when the ball stud is rotated, so that the durability of the body portion is lowered.

Japanese Patent Laying-Open No. 2015-7444 Japanese Utility Model Publication No. 3-123161

  An object of the present invention is to provide a dust cover and a sealing structure that are improved in sealing performance without increasing the number of parts.

  The present invention employs the following means in order to solve the above problems.

That is, the dust cover of the present invention is
A ball stud having a spherical portion at one end of a shaft portion having a flange portion, a socket having a bearing of the spherical portion and supporting the ball stud so as to be rotatable and swingable, and the spherical portion via the flange portion In a dust cover used for a ball joint including a coupling member coupled to the shaft portion on the opposite side,
A deformable body part, a fixed part provided on one end side of the body part and fixed to the socket, and provided on the other end side of the body part, and slidable with respect to the shaft part and the coupling member, respectively. A seal body made of an elastic body integrally having a seal portion provided movably;
A reinforcing ring provided inside the seal portion;
A dust cover comprising:
The seal portion is
An inner peripheral seal portion having a plurality of annular convex portions slidable with respect to the outer peripheral surface of the shaft portion;
A dust seal portion slidable with respect to the end face of the coupling member;
With
Of the plurality of annular convex portions, the one end side convex portion closest to the one end side is formed by an annular concave portion recessed from the end surface on the one end side toward the other end side in the seal portion, and an inner peripheral surface of the seal portion. And formed so as to protrude toward the one end side,
The inner peripheral surface of the one end-side convex portion is configured to be slidably in close contact with the outer peripheral surface of the flange portion.

Moreover, according to the sealing structure of the present invention,
A ball stud having a spherical portion at one end of a shaft portion having a flange portion, a socket having a bearing of the spherical portion and supporting the ball stud so as to be rotatable and swingable, and the spherical portion via the flange portion A ball joint having a coupling member coupled to the shaft portion on the opposite side, and
A dust cover used for the ball joint;
In a sealing structure comprising:
The dust cover is
A deformable body part, a fixed part provided on one end side of the body part and fixed to the socket, and provided on the other end side of the body part, and slidable with respect to the shaft part and the coupling member, respectively. A seal body made of an elastic body integrally having a seal portion provided movably;
A reinforcing ring provided inside the seal portion;
With
The seal portion is
An inner peripheral seal portion having a plurality of annular convex portions slidable with respect to the outer peripheral surface of the shaft portion;
A dust seal portion slidable with respect to the end face of the coupling member;
With
Of the plurality of annular convex portions, the one end side convex portion closest to the one end side is formed by an annular concave portion recessed from the end surface on the one end side toward the other end side in the seal portion, and an inner peripheral surface of the seal portion. And formed so as to protrude toward the one end side,
The inner peripheral surface of the one end-side convex portion is configured to be slidably in close contact with the outer peripheral surface of the flange portion.

  According to these inventions, the inner peripheral surface of the one end side convex portion formed so as to protrude toward the one end side is slidably adhered to the outer peripheral surface of the collar portion provided on the shaft portion of the ball stud. It is configured as follows. Thereby, irrespective of the attitude | position of a ball stud with respect to a socket, the attitude | position of the seal part with respect to a ball stud and a coupling member can be maintained stably. Thereby, the sealing performance by the seal portion is stably exhibited regardless of the attitude of the ball stud with respect to the socket. Moreover, the one end side convex part is formed by the annular recessed part dented toward the other end side from the end surface of the one end side in the seal part, and the inner peripheral surface of the seal part. Therefore, even if the one end side convex portion is pushed in by the collar portion, the one end side convex portion can be bent toward the annular concave portion side. Thereby, it can suppress that a compressive force larger than necessary is added to a convex part at the one end side.

  The end face on the one end side of the reinforcing ring may be located on the other end side with respect to the one end side convex portion.

  Thereby, when a compressive force acts on one end side convex part, it can further suppress that one end side convex part deform | transforms abnormally.

  The inner peripheral surface of the one end side convex portion is configured by an inclined surface that increases in diameter toward the one end side, and the outer peripheral surface of the one end side convex portion is configured by an inclined surface that decreases in diameter toward the one end side. It is good to be.

  Thereby, moderate force can be made to act on the one end side convex part toward the radially outer side and the other end side from the collar part. Accordingly, it is possible to appropriately maintain the adhesion of the dust seal portion to the coupling member.

  In addition, said each structure can be employ | adopted combining as much as possible.

  As described above, according to the present invention, the sealing performance can be improved without increasing the number of parts.

FIG. 1 is a schematic cross-sectional view of a ball joint and a dust cover attached to the ball joint according to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view of a dust cover according to an embodiment of the present invention. FIG. 3 is an enlarged schematic cross-sectional view of the vicinity of the seal portion in the dust cover according to the embodiment of the present invention. FIG. 4 is an enlarged schematic cross-sectional view of the vicinity of the seal portion of the dust cover in a state where the dust cover according to the embodiment of the present invention is attached to the ball joint. FIG. 5 is a schematic cross-sectional view of a conventional ball joint and a dust cover attached to the ball joint.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be exemplarily described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention only to those unless otherwise specified. .

(Example)
With reference to FIGS. 1-4, the dust cover and sealing structure based on the Example of this invention are demonstrated. FIG. 1 is a schematic cross-sectional view of a ball joint and a dust cover attached to the ball joint according to an embodiment of the present invention. FIG. 1 shows a cross-sectional view taken along a plane including the central axis of the shaft portion of the ball stud provided in the ball joint. FIG. 2 is a schematic cross-sectional view of a dust cover according to an embodiment of the present invention. FIG. 2 is a cross-sectional view taken along a plane including the central axis of the annular dust cover in a state where the dust cover is not deformed. FIG. 3 is a partially enlarged view of FIG. 2, and is a schematic cross-sectional view in which the vicinity of the seal portion in the dust cover according to the embodiment of the present invention is enlarged. FIG. 4 is a partially enlarged view of FIG. 1, and is a schematic cross-sectional view in which the vicinity of the seal portion of the dust cover is enlarged in a state where the dust cover according to the embodiment of the present invention is attached to the ball joint.

<Ball joint>
In particular, an example of a ball joint to which the dust cover according to the present embodiment can be applied will be described with reference to FIG. The ball joint includes a ball stud 300, a socket 200 that supports the ball stud 300 so as to be rotatable and swingable, and a knuckle 400 as a coupling member that is coupled to the shaft portion 310 of the ball stud 300.

  The ball stud 300 has a spherical portion 320 at one end of a shaft portion 310 having a flange portion 311. The socket 200 includes an annular case 210, a bottom plate 220 fixed to the bottom side of the case 210, and a bearing 230 of a spherical portion 320. The bearing 230 has a bearing surface 231 formed of a spherical surface having the same diameter as the radius of curvature of the spherical portion 320. The knuckle 400 is coupled to the shaft portion 310 on the side opposite to the spherical portion 320 via the flange portion 311. The knuckle 400 is coupled to the shaft portion 310 by a nut 500.

  A dust cover 100 is used to prevent water and dust from entering the joint portion and to prevent the grease from flowing out from the joint portion.

<Dust cover>
The overall configuration of the dust cover 100 will be described with reference to FIG. The dust cover 100 includes a seal body made of an elastic material such as rubber (for example, chloroprene rubber) and a reinforcing ring 150 made of resin such as PTFE, nylon, and polyamide. In this embodiment, after the resin-made reinforcing ring 150 is molded, an adhesive is applied to the reinforcing ring 150, set in a mold, and a rubber material is injected into the mold. The dust cover 100 can be obtained by vulcanization molding. Note that a metal may be used as the material of the reinforcing ring 150.

  The seal body includes a deformable annular and membrane-shaped body portion 110, a fixed portion 130 that is provided on one end side of the body portion 110 and is fixed to the socket 200, and a seal that is provided on the other end side of the body portion 110. The unit 120 is integrally formed. Hereinafter, the side where the fixed part 130 is provided (the lower side in FIGS. 2, 3 and 4) with respect to the body part 110 is referred to as “one end side”, and the side where the seal part 120 is provided (FIG. 2). , 3 and 4) is referred to as “other end side”.

  The fixed portion 130 is provided with an annular recess 131. When the clamp 600 is fitted into the annular recess 131, the fixed part 130 is fixed to the case 210 of the socket 200. The reinforcing ring 150 is provided inside the seal portion 120. In the dust cover 100 configured as described above, when the ball stud 300 swings with respect to the socket 200, the body portion 110 is deformed (see FIG. 1). When the ball stud 300 rotates with respect to the socket 200, the seal portion 120 slides with respect to the shaft portion 310 and the knuckle 400 of the ball stud 300, respectively. With the sealing structure configured as described above, the dust cover 100 provides a sealing function regardless of whether the ball stud 300 swings or rotates with respect to the socket 200.

<Seal and reinforcement ring>
The seal part 120 and the reinforcing ring 150 according to the present embodiment will be described in more detail with reference to FIGS. 3 and 4 in particular.

  The seal portion 120 includes an inner peripheral seal portion having a plurality of annular convex portions slidable with respect to the outer peripheral surface of the shaft portion 310 of the ball stud 300, and a dust seal portion slidable with respect to the end surface of the knuckle 400. I have. For convenience of explanation, the plurality of annular convex portions are referred to as a first convex portion 121a, a second convex portion 121b, and a third convex portion 121c in order from the other end side to the one end side. Here, among the plurality of annular convex portions, the one end side convex portion on the most end side corresponds to the third convex portion 121c.

  Each of the first convex portion 121a and the second convex portion 121b is configured by an annular convex portion that protrudes radially inward. And these 1st convex part 121a and 2nd convex part 121b are comprised so that it may slidably contact | adhere to the outer peripheral surface of the main-body part (part except the collar part 311) of the axial part 310 (FIG. 4). Further, the inner diameter of the most distal portion on the radially inner side of the first convex portion 121a is designed to be larger than the inner diameter of the most distal portion on the radially inner side of the second convex portion 121b.

  And the 3rd convex part 121c is formed so that it may protrude toward one end side by the annular recessed part 123 dented toward the other end side from the end surface of the one end side in the seal part 120, and the inner peripheral surface of the seal part 120. Has been. The inner peripheral surface 121c1 of the third convex portion 121c is configured to be slidably in close contact with the outer peripheral surface of the flange portion 311 (see FIG. 4). Further, the inner peripheral surface 121c1 of the third convex portion 121c is configured by an inclined surface that expands toward one end side, and the outer peripheral surface 121c2 of the third convex portion 121c is configured by an inclined surface that decreases in diameter toward the one end side. Has been. In the present embodiment, the inner peripheral surface 121c1 and the outer peripheral surface 121c2 are both mostly tapered surfaces.

  The dust seal part according to the present embodiment includes a dust lip 122a provided on the radially outer side and an annular convex part 122b provided on the radially inner side. Dustrip 122 a is configured to extend radially outward and toward the surface side of knuckle 400.

  The reinforcing ring 150 includes a cylindrical portion 151 and an inward flange portion 152 provided on the other end side of the cylindrical portion 151. The distal end of the inward flange portion 152 in the reinforcing ring 150 is the axial direction between the most distal portion on the radially inner side of the first convex portion 121a and the most distal portion on the radially inner side of the second convex portion 121b in the seal portion 120. It is provided so as to be located between them. Further, the end surface 151a on one end side of the reinforcing ring 150 is located on the other end side with respect to the third convex portion 121c. Note that F in FIG. 3 indicates the position of the end surface 151 a on one end side of the reinforcing ring 150. In the figure, H indicates the height of the third convex portion 121c. The height H of the 3rd convex part 121c which concerns on a present Example is set so that it may become 1 mm or more. And the distance from the end surface of the one end side in the seal part 120 to the end surface 151a of the one end side of the reinforcing ring 150 is set to be not less than the height H of the third convex portion 121c. Furthermore, the compression allowance (corresponding to the area h (see FIG. 3) compressed by the outer peripheral surface of the flange 311) in the third convex portion 121c is set to be equal to or less than the height H of the third convex portion 121c. ing. Thereby, it can suppress that an excessive compressive force acts with respect to the 3rd convex part 121c, and can suppress that the 3rd convex part 121c deform | transforms abnormally.

<Excellent points of dust cover and sealing structure according to this embodiment>
According to the dust cover 100 and the sealing structure according to the present embodiment, the inner peripheral seal portion of the seal portion 120 of the dust cover 100 is provided with the third convex portion 121c formed so as to protrude toward one end side. ing. And the inner peripheral surface 121c1 of this 3rd convex part 121c is comprised so that it may slidably contact | adhere to the outer peripheral surface of the collar part 311 provided in the axial part 310 of the ball stud 300. FIG. As a result, one end side and the inner peripheral surface side of the seal portion 120 are supported by the flange portion 311. Therefore, regardless of the attitude of the ball stud 300 with respect to the socket 200, the attitude of the seal portion 120 with respect to the ball stud 300 and the knuckle 400 can be stably maintained. Thereby, irrespective of the attitude of the ball stud 300 with respect to the socket 200, the sealing performance by the seal portion 120 is stably exhibited.

  The third convex portion 121 c is formed by an annular concave portion 123 that is recessed from the end surface on one end side of the seal portion 120 toward the other end side, and the inner peripheral surface of the seal portion 120. Therefore, even if the third convex portion 121c is pushed in by the flange portion 311, the third convex portion 121c can be bent toward the annular concave portion 123 side. Thereby, it can suppress that the compressive force larger than necessary is added to the 3rd convex part 121c. Accordingly, it is possible to prevent the third convex portion 121c from being deformed abnormally or a large force from being applied to the dust seal portion due to the third convex portion 121c being compressed. .

  In the present embodiment, the end surface 151a on one end side of the reinforcing ring 150 is located on the other end side with respect to the third convex portion 121c. Thereby, when the compressive force acts on the 3rd convex part 121c, it can further suppress that the 3rd convex part 121c deform | transforms abnormally.

  Furthermore, in the present embodiment, the inner peripheral surface 121c1 of the third convex portion 121c is configured by an inclined surface that increases in diameter toward one end side, and the outer peripheral surface 121c2 of the third convex portion 121c contracts toward one end side. It is comprised by the inclined surface which diameters. Thereby, an appropriate force can be applied to the third convex portion 121c from the flange portion 311 toward the radially outer side and the other end side. Accordingly, it is possible to appropriately maintain the adhesion of the dust seal portion (particularly, the dust lip 122a) to the knuckle 400. Further, even when a large force is applied from the knuckle 400 to the dust seal portion, the third convex portion 121c can move so as to get over the flange portion 311 and thus the third convex portion 121 is prevented from being crushed. be able to.

DESCRIPTION OF SYMBOLS 100 Dust cover 110 Body part 120 Seal part 121a 1st convex part 121b 2nd convex part 121c 3rd convex part 121c1 Inner peripheral surface 121c2 Outer peripheral surface 122a Dustrip 122b Annular convex part 123 Annular concave part 130 Fixed part 131 Annular concave part 150 Reinforcement Ring 151 Cylindrical portion 151a End surface 152 Inward flange portion 200 Socket 210 Case 220 Bottom plate 230 Bearing 231 Bearing surface 300 Ball stud 310 Shaft portion 311 Hook portion 320 Spherical portion 400 Knuckle 500 Nut 600 Clamp

Claims (6)

A ball stud having a spherical portion at one end of a shaft portion having a flange portion, a socket having a bearing of the spherical portion and supporting the ball stud so as to be rotatable and swingable, and the spherical portion via the flange portion In a dust cover used for a ball joint including a coupling member coupled to the shaft portion on the opposite side,
A deformable body part, a fixed part provided on one end side of the body part and fixed to the socket, and provided on the other end side of the body part, and slidable with respect to the shaft part and the coupling member, respectively. A seal body made of an elastic body integrally having a seal portion provided movably;
A reinforcing ring provided inside the seal portion;
A dust cover comprising:
The seal portion is
An inner peripheral seal portion having a plurality of annular convex portions slidable with respect to the outer peripheral surface of the shaft portion;
A dust seal portion slidable with respect to the end face of the coupling member;
With
Of the plurality of annular convex portions, the one end side convex portion closest to the one end side is formed by an annular concave portion recessed from the end surface on the one end side toward the other end side in the seal portion, and an inner peripheral surface of the seal portion. And formed so as to protrude toward the one end side,
The dust cover according to claim 1, wherein an inner peripheral surface of the one end side convex portion is configured to be slidably in close contact with an outer peripheral surface of the flange portion.   2. The dust cover according to claim 1, wherein an end face on the one end side of the reinforcing ring is located on the other end side with respect to the one end side convex portion.   The inner peripheral surface of the one end side convex portion is configured by an inclined surface that increases in diameter toward the one end side, and the outer peripheral surface of the one end side convex portion is configured by an inclined surface that decreases in diameter toward the one end side. The dust cover according to claim 1, wherein the dust cover is provided. A ball stud having a spherical portion at one end of a shaft portion having a flange portion, a socket having a bearing of the spherical portion and supporting the ball stud so as to be rotatable and swingable, and the spherical portion via the flange portion A ball joint having a coupling member coupled to the shaft portion on the opposite side, and
A dust cover used for the ball joint;
In a sealing structure comprising:
The dust cover is
A deformable body part, a fixed part provided on one end side of the body part and fixed to the socket, and provided on the other end side of the body part, and slidable with respect to the shaft part and the coupling member, respectively. A seal body made of an elastic body integrally having a seal portion provided movably;
A reinforcing ring provided inside the seal portion;
With
The seal portion is
An inner peripheral seal portion having a plurality of annular convex portions slidable with respect to the outer peripheral surface of the shaft portion;
A dust seal portion slidable with respect to the end face of the coupling member;
With
Of the plurality of annular convex portions, the one end side convex portion closest to the one end side is formed by an annular concave portion recessed from the end surface on the one end side toward the other end side in the seal portion, and an inner peripheral surface of the seal portion. And formed so as to protrude toward the one end side,
The sealing structure according to claim 1, wherein an inner peripheral surface of the one end side convex portion is configured to be slidably in close contact with an outer peripheral surface of the flange portion.   The sealing structure according to claim 4, wherein an end face on the one end side of the reinforcing ring is located on the other end side with respect to the one end side convex portion.   The inner peripheral surface of the one end side convex portion is configured by an inclined surface that increases in diameter toward the one end side, and the outer peripheral surface of the one end side convex portion is configured by an inclined surface that decreases in diameter toward the one end side. The sealing structure according to claim 4 or 5, wherein

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